(a) Field of the Invention
The present invention relates to a thin film array panel and a manufacturing method thereof.
(b) Description of the Related Art
Generally, a thin film array panel is used for display devices such as liquid crystal displays (LCDs) and organic light emitting displays (OLED).
The LCD is one of the most widely used flat panel displays since it is lightweight and occupies less space than conventional cathode ray tube (CRT) displays. The general structure of an LCD consists of a liquid crystal (LC) layer that is positioned between a pair of panels including field generating electrodes and polarizers. The LC layer is subjected to an electric field generated by the electrodes and variations in the field strength change the molecular orientation of the LC layer. For example, upon application of an electric field, the molecules of the LC layer change their orientation to change the polarization of light passing through the LC layer. Appropriately positioned polarizing filters selectively block the polarized light, creating dark areas that can represent desired images.
The thin film array panel for display device generally includes a plurality of pixel electrodes, a plurality of thin film transistors (TFTs) for controlling signals to be applied to the pixel electrodes, and a plurality of signal lines transmitting the signals.
The signal lines are made of low resistivity material such as Al or Al alloy and the signal lines contacting semiconductor further include a refractory metal film. However, since Al containing metal has poor physical and chemical characteristics, several methods for compensating the weak characteristics are suggested. One of the methods is to anodize the Al containing metal. Another example is to add a compensating conductor made of indium tin oxide (ITO) or indium zinc oxide (IZO), which is used for pixel electrodes, on the Al containing metal. However, the contact between the Al containing metal and ITO and IZO is poor, another metal is required to be disposed between the Al containing metal and the compensating conductor.
Mo or Mo alloy is suggested to be a substitute for Al containing metal since it has low resistivity and good contact characteristics with ITO or IZO. However, the Mo containing metal has poor chemical resistance and thus it may be easily corroded under a chemically active circumference such as when another film or layer is being etched.